JPH08220027A - X-ray fluorescence analyzer - Google Patents

Abstract

PURPOSE: To provide the X-ray fluorescence analyzer, which can improve the intensity of exciting X rays and the measuring accuracy, by suppressing the deterioration of the X-ray intensity caused by the generation of X-ray monochrome as much as possible. CONSTITUTION: An X-ray fluorescence analyzer 1 is constituted of an X-ray generator 10, a spectral crystal 13, which generates the monochrome from the X rays generated in the X-ray generator 10, an X-ray detector 20 for detecting fluorescent X rays 5, which are generated from a sample 2 by casting X-ray fluxes on the sample 2, a preamplifier 21, a proportional amplifier 22, a pulse height analyzer 23, a data processor 24 and the like. The crystal surface of the spectral crystal 13 is curved in the shape of the cured surface. The spectral crystal 13, an X-ray focal point A of the X-ray generator 10 and an irradiated position B of the sample 2 are arranged on the circumference of a Rowland circle RC with a radius R, respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention irradiates a sample such as a silicon wafer with excited X-rays to emit fluorescent X-rays from the sample, for example, in an energy dispersion system (EDX: Energy Dispersion).
Fluorescence X for analysis with a persive X-ray spectrometer
The present invention relates to a line analyzer.

[0002]

2. Description of the Related Art Conventionally, a sample such as a silicon wafer having an optically smooth plane is irradiated with X-rays at a low incident angle to detect fluorescent X-rays from an element existing near the surface of the sample. Total reflection X-ray Fluorescence analyzer is known, which obtains information only near the surface of the sample with a high S / N ratio by totally reflecting the excited X-rays on the sample surface. be able to.

The X-ray spectrum emitted by the X-ray source is
Depends on the anticathode material, applied voltage, applied current, etc., and generally shows continuous X-rays (white X-rays) showing a continuous spectrum distribution due to bremsstrahlung of thermoelectrons, and a sharp peak peculiar to the anticathode material. Characteristic X-rays are superimposed.

Therefore, a single characteristic X-ray is separated from the characteristic X-ray generated from the anticathode of the X-ray generation source by a spectroscopic means including a dispersive crystal and a slit, and then the sample is irradiated with monochrome total reflection fluorescence. X-ray analyzer (Japanese Patent Application No. 1-272)
No. 124) has been proposed and the background noise is reduced by monochromatic excitation X-rays, and the detection limit of trace elements is improved. Therefore, especially in the field of trace element contamination detection on semiconductor wafers for ICs. It is spreading rapidly.

Besides, a pair of X's having different wavelength ranges of excited X-rays.
An X-ray fluorescence analyzer has been disclosed in which a plurality of radiation sources and analyzing crystals are provided and the excitation wavelength of monochromatic X-rays is sequentially switched to diversify the elements to be analyzed (JP-A-6-
No. 174664 (Japanese Patent Application No. 4-350602).

Among contaminants on a silicon wafer, for example, elements such as Fe, Ni, Cu, Zn, Al, and Na are important analysis targets, and in order to set the detection sensitivity to these elements to the maximum. , W (tungsten) and the like, using an X-ray generation source equipped with an anticathode, among the characteristic X-rays of W, Lβ1 line (9.671 keV) is excited X
Used as a line. The reason is that (a) W is generally widely used as a material for the anticathode from the standpoint of life and X-ray emission characteristics, and (b) W- can be applied. Lβ1 line is K of Zn
Since it has the lowest energy among the main characteristic X-rays of an anticathode material higher than the absorption edge (9.660 keV) and having a long life like W, for example, Mo, Ag, and Rh,
The excitation efficiency of exciting the element to be analyzed is excellent and the like.

[0007]

With the recent increase in the density of integrated circuits, the control of the surface contamination of silicon wafers tends to be emphasized, so that the detection limit of trace elements is further improved, and in a short time. A measurable analytical method is required.

A conventional monochromatic X-ray fluorescence analyzer uses a dispersive crystal having a flat crystal surface. When X-rays from an X-ray generation source are diffracted by the dispersive crystal, the diffraction directions are different according to wavelengths according to Bragg conditions. Spread. Therefore, if a monochromatic X-ray diffracted in a predetermined direction is extracted using a slit or the like, the intensity of the excitation X-ray for irradiating the sample becomes considerably small, and it is attempted to secure a predetermined S / N ratio and wavelength resolution. Then, the measurement time becomes long.

An object of the present invention is to provide a fluorescent X-ray analyzer capable of suppressing the decrease in X-ray intensity due to monochromatic X-rays as much as possible and improving the excitation X-ray intensity and measurement accuracy. .

[0010]

According to the present invention, there is provided an X-ray generating means for generating X-rays for excitation, an X-ray diffracting means for monochromating the X-rays generated by the X-ray generating means, and In a fluorescent X-ray analysis apparatus, which comprises an X-ray detection unit for irradiating a sample with monochromatic X-rays separated by the X-ray diffraction unit and detecting fluorescent X-rays generated from the sample, the X-ray diffraction unit is A fluorescent X-ray having a dispersive crystal whose crystal plane is curved, wherein the dispersive crystal, the X-ray focal point of the X-ray generating means, and the irradiation position of the sample are respectively arranged on the Rowland circle. It is an analyzer. Further, according to the present invention, the X-ray generating means for generating X-rays for excitation, the X-ray diffracting means for monochromaticizing the X-rays generated by the X-ray generating means, and the X-ray diffracting means are separated. Irradiate the sample with monochromatic X-rays,
In an X-ray fluorescence analyzer including X-ray detection means for detecting X-ray fluorescence generated from a sample, the X-ray diffraction means is a dispersive crystal whose crystal plane is curved in a shape forming a part of an ellipse. In addition, the X-ray focal point of the X-ray generating means and the irradiation position of the sample are arranged at the focal point of the ellipse, respectively. Further, according to the present invention, the X-ray generating means for generating X-rays for excitation, the X-ray diffracting means for monochromaticizing the X-rays generated by the X-ray generating means, and the X-ray diffracting means are separated. In a fluorescent X-ray analysis device comprising an X-ray detection means for irradiating a sample with monochromatic X-rays and detecting fluorescent X-rays generated from the sample, in the X-ray diffraction means, the crystal plane is a part of a parabola. It is a dispersive crystal which is curved in a shape that forms, and the X-ray focal point of the X-ray generating means is arranged at the focal point of the parabola, which is an X-ray fluorescence analyzer. Further, the present invention is characterized in that X-rays are irradiated so as to be totally reflected on the sample surface, and fluorescent X-rays generated from the sample surface in directions other than the total reflection direction are detected. According to the present invention, the X-ray diffracting means sets the X-ray incident angle and the X-ray diffraction angle with respect to the diffraction grating surface to θ, the surface spacing of the diffraction grating surface to d, and the wavelength of the monochromatic X-ray to λ, and the Bragg condition 2. d · sin θ = n · λ (where n is a natural number of 1 or more), and diffraction is performed so that the wavelength λ becomes constant even if the X-ray incident angle θ changes depending on the X-ray incident position. It is characterized in that the lattice spacing d changes depending on the location.

[0011]

According to the present invention, by using a dispersive crystal having a curved crystal surface as the X-ray diffraction means,
Focusing on X-rays of a specific wavelength, it is possible to configure a converging optical system in which X-rays diverging from one point converge again to one point. Therefore, when the X-ray flux emitted from the X-ray focal point has a spread at a predetermined divergence angle, the dispersive crystal, the X-ray focal point of the X-ray generating means, and the irradiation position of the sample are respectively arranged on the Rowland circle, X-rays monochromated by the dispersive crystal can be efficiently focused on the sample. Therefore, the utilization efficiency of X-rays from the X-ray generation means is improved, and the intensity of excited X-rays can be significantly increased.

Further, according to the present invention, as the X-ray diffracting means, by using a dispersive crystal having a crystal surface curved in a shape forming a part of an ellipse, the X-ray of a specific wavelength can be obtained as described above.
Focusing on the line, it is possible to configure a converging optical system in which the X-ray diverging from one point converges again to one point. So X
When the X-ray flux radiated from the line focus has a divergence at a predetermined divergence angle, the X-ray focus and the irradiation position of the sample are respectively arranged at the focal points of the ellipses, so that the X-ray monochromated by the dispersive crystal is obtained. It can be efficiently focused on the sample. Therefore, the X-ray utilization efficiency is improved,
The intensity of the excited X-ray can be remarkably increased.

According to the present invention, as the X-ray diffracting means, by using a dispersive crystal whose crystal plane is curved in the shape of a part of a parabola, focusing on X-rays of a specific wavelength as described above, It is possible to configure a focusing optical system in which X-rays diverging from one point are converged into a parallel beam. Therefore, when the X-ray flux radiated from the X-ray focal point has a spread at a predetermined divergence angle, the X-ray focal point is arranged at the focal point of the parabola so that the X-ray monochromated by the dispersive crystal can be efficiently reflected on the sample. It can be well converged. Therefore, the X-ray utilization efficiency is improved, and the intensity of excited X-rays can be significantly increased.

Further, by irradiating the sample surface with X-rays and detecting fluorescent X-rays generated from the sample surface in a direction other than the total reflection direction, total reflection for analyzing only the vicinity of the surface of the sample. Fluorescence analysis becomes possible, and particularly, qualitative analysis and quantitative analysis of surface contaminant elements become easy.

Further, using a dispersive crystal as the X-ray diffracting means, the X-ray incident angle with respect to the diffraction grating surface is θ, the surface spacing of the diffraction grating surface is d, and the wavelength of the monochromatic X-ray is λ. d · sin θ = n · λ (where n is a natural number of 1 or more) and X is determined according to the X-ray incident position.
Even if the line incident angle θ changes, the surface spacing d of the diffraction grating surface changes depending on the position so that the wavelength λ becomes constant, so that the X-ray convergence can be achieved without degrading the monochromaticity of the diffracted X-ray. It will be possible.

[0016]

FIG. 1 is a block diagram showing an embodiment of the present invention. The X-ray fluorescence analyzer 1 is composed of a rotating anticathode 11 made of W (tungsten), Mo (molybdenum), or the like, and an X including a filament 12 that emits thermoelectrons.
The X-ray generator 10, the dispersive crystal 13 and the collimators 14 and 15 for separating the X-ray flux 4 such as W-Mα characteristic X-rays from the X-ray flux 3 radiated from the X-ray generator 10, and the monochromatic X The ray bundle 4 is incident on the sample 2 such as a silicon wafer,
An X-ray counter 17 such as a scintillation counter for measuring the intensity of X-rays that are totally reflected on the surface and passed through the slit 16, and a lithium drift type Si detector for detecting the fluorescent X-rays 5 generated from the sample 2. And the X-ray detector 20.

The output signal from the X-ray detector 20 is input to the preamplifier 21 and converted into a step-like voltage pulse having the time integrated value of the charge pulse at the wave height. The output signal from the preamplifier 21 is input to the proportional amplifier 23 and shaped into a pulse having a wave height proportional to the rising width of the voltage pulse. The output signal from the proportional amplifier 23 is input to the wave height analyzer 23, and the count rate of each wave height value is measured. The data processing unit 24 processes the data measured by the wave height analyzer 23 and stores the data in a magnetic disk, and also performs screen display and printing.

The table drive unit 25 drives a moving table that determines the three-dimensional position and orientation of the sample 2. The control unit 26 controls the table driving unit 25 based on a command from the data processing unit 24.

As the dispersive crystal 13, LiF, yellow cobblestone, S
i, NaCl, calcite, Ge, α-quartz, graphite, InS
b, pentaerythritol, or a SiW artificial cumulative film in which a plurality of Si layers and W layers are alternately deposited on a substrate is used. By selecting the X-ray incident direction and the orientation of a particular diffraction grating surface, Diffract only the X-rays you have in a certain direction,
Has a function of reflecting.

The crystal plane of the dispersive crystal 13 is curved into a curved surface with a predetermined radius of curvature, and as with an optical system using a concave mirror, the X-ray diverging from one point is again 1 with respect to the X-ray of a specific wavelength. It forms a centralized optical system that converges to a point. The dispersive crystal 13, the X-ray focal point A of the X-ray generator 10 and the irradiation position B of the sample 2 are respectively arranged on the circumference of a Roland circle RC having a radius R, and radiate from the X-ray focal point A at a predetermined divergence angle. The generated X-ray flux 3 is diffracted by the dispersive crystal 13, and the sample 2
The irradiation position B is efficiently converged.

FIG. 2 is a schematic view showing the arrangement of the dispersive crystal 13, the X-ray focal point A and the irradiation position B in FIG. 1, which is also called a Johansson type arrangement. The dispersive crystal 13 slightly bends a flexible thin crystal to form a crystal plane 13
The radius of curvature of b is set to 2R. Further, the surface 13a on which the X-rays are incident is processed into a cylindrical surface by polishing, etching or the like so as to match the shape of the Rowland circle RC having a radius R. The X-ray focal point A of the X-ray generator 10 and the irradiation position B of the sample 2 are arranged on the Rowland circle RC.

The X-rays emitted from the X-ray focal point A at the divergence angle α are diffracted and reflected by the crystal plane 13b of the dispersive crystal 13, and then,
It converges toward the irradiation position B at a convergence angle β. At this time, the divergence angle α coincides with the convergence angle β (α = β), and the intersection angle ψ of two straight lines connecting the X-ray focal point A, each point on the surface 13a and the irradiation position B is constant from a geometrical consideration. become. Further, the angle θ at which each straight line intersects the tangent to the crystal plane 13b, that is, the X-ray incident angle and the X-ray diffraction angle are also constant. Therefore, focusing on the X-ray of the specific wavelength, the Bragg condition is satisfied at an arbitrary position of the dispersive crystal 13, and the concentrated optical system for the monochromatic X-ray can be configured. Thus X
The X-ray utilization efficiency is improved together with the monochromaticization of the rays, and the irradiation intensity on the sample 2 can be significantly increased.

Returning to FIG. 1, the X-ray detector 20 and the preamplifier 21 avoid the effects of dark current and thermal noise.
It is kept at a temperature extremely lower than room temperature by a cooling means such as liquid nitrogen. Further, in order to prevent an increase in background due to scattered X-rays and generation of characteristic X-rays of argon in the air due to the influence of X-ray scattering due to air, the excitation X
The space through which the X-ray or the fluorescent X-ray passes is preferably maintained in a vacuum of 0.1 Torr or less.

Next, the operation will be described. X-ray generator 1
At 0, when the thermoelectrons generated from the filament 12 are incident on the rotating anticathode 11, for example, Lα rays (8.396 keV) and Lβ1 rays (9.671) which are characteristic X-rays of W.
keV), Lβ2 rays (9.960 keV) and Mα rays (1.774 keV) as well as white X-rays. When such an X-ray flux 3 is incident on the dispersive crystal 13 made of, for example, LiF at an angle θ, only the W-Mα rays are reflected at the angle θ and separated by the lattice plane having the plane index (200). By making the excited X-rays monochromatic in this manner, it is possible to reduce the intensity of scattered radiation that constitutes the signal background. The separated X-ray flux 4 passes through the collimators 14 and 15 and is incident on the sample 2 at an extremely low angle, for example, an angle of 0.1 degree or less. In this way, elements existing near the surface of the sample 2, in particular, surface contamination elements, such as elements having a K absorption edge lower than the W-Mα line, such as Fe, Ni, Cu, Zn, Al, and Na, are excited, Fluorescent X-rays 5 peculiar to each element are generated.

Fluorescent X-ray 5 generated from the contaminant element of sample 2
Is detected by the X-ray detector 20 and converted into an electron-hole pair according to the energy of the X-ray photon, so the intensity of the output signal is proportional to the energy of the detected X-ray photon. Therefore, the energy spectrum of the fluorescent X-rays 5 can be obtained by measuring the intensity of the output signal of the X-ray detector 20.

The next preamplifier 21 is provided with a negative feedback circuit by an electrostatic capacitance between the input and output, and converts the time integrated value of the input charge pulse into a stepped voltage pulse having a wave height. The following proportional amplifier 22 includes, for example, a Gaussian-type filter for removing noise, a pile-up rejector for removing a pile-up in which two or more X-ray photons enter in a short time, and the like. The signal is converted into a pulse signal having a wave height proportional to the rising width of the pulse. The next wave height analyzer 23 includes, for example, a Wilkinson type A / D converter, converts into a number of clock pulses proportional to the wave height value of the input pulse, and counts for each specific channel corresponding to the number of clock pulses. And store it in memory. The data stored in the memory is converted by the data processor 24 into an energy spectrum having a channel (energy) on the horizontal axis and a count value on the vertical axis. In this way, by analyzing the obtained energy spectrum, the elemental composition of the specific region of the sample 2 can be known, and the contamination map of the sample 2 can be created by scanning the sample 2 by the table driving unit 25.

FIG. 3 is a block diagram showing another embodiment of the present invention. The fluorescent X-ray analyzer 1 has the same configuration as that of FIG. 1, and has an X-ray generator 10 including a rotating anticathode 11 and a filament 12, an X-ray flux 3 from the X-ray generator 10, and W-Mα characteristics. Spectroscopic crystal 13 and collimators 14, 15 for separating X-ray flux 4 having a narrow wavelength width such as X-rays
Then, the X-ray flux 4 is incident on the sample 2, the X-ray counter 17 that measures the intensity of the X-rays that are totally reflected on the surface thereof and passed through the slit 16, and the fluorescent X-rays 5 generated from the sample 2 are detected. The X-ray detector 20 and the like are used.

Since the signal processing system and the sample driving system subsequent to the X-ray detector 20 are the same as those in FIG. 1, the same reference numerals are given and duplicate description will be omitted.

As the dispersive crystal 13, as in FIG.
An F or SiW artificial cumulative film or the like is used, and only the X-ray having a specific wavelength is diffracted and reflected in a certain direction by selecting the incident direction of the X-ray and the orientation of the specific diffraction grating surface.

FIG. 4 is a schematic view showing an example of the arrangement of the dispersive crystal 13, the X-ray focus A and the irradiation position B in FIG. The dispersive crystal 13 slightly bends a flexible thin crystal, and the crystal plane is curved to form a part of an ellipse EC. As with an optical system using an elliptical mirror, the X-ray of a specific wavelength is used. With respect to the above, an X-ray diverging from one point constitutes a converging optical system that converges again to one point. X-ray focus A of the X-ray generator 10
The irradiation position B of the sample 2 is arranged at each focus of the ellipse EC.

The X-rays emitted from the X-ray focal point A at the divergence angle α are diffracted and reflected by the crystal plane of the dispersive crystal 13, and then converge at the convergence angle β toward the irradiation position B. Where ellipse EC
The convergence angle β can be made extremely smaller than the divergence angle α by setting the position of the dispersive crystal 13 forming a part of the above to the X-ray focus A side and making the ellipse EC flatter.

On the other hand, in the X-ray fluorescence analyzer shown in FIG. 1, when the X-ray flux 4 is made incident on the surface of the sample 2 at a total reflection angle, the convergence angle β of the X-ray flux 4 is the total reflection critical angle φc.
Unless otherwise, X-rays that deviate from the total reflection condition appear. Therefore, in order to perform total internal reflection fluorescence analysis, α = β
It is necessary to satisfy <φc. The critical angle for total reflection φc is generally a very small value, and for example, φc = 0.17 when a silicon wafer is irradiated with 9.67 keV X-rays.
It becomes degree. Therefore, when the arrangement of FIG. 1 is applied to the total reflection fluorescence analysis, it is necessary to make the divergence angle α from the X-ray focus A extremely small.

On the other hand, in the arrangement of FIG. 3, since the convergence angle β can be made smaller than the divergence angle α, it becomes easy to satisfy the condition of total reflection for the sample 2. In this way, the efficiency of X-ray utilization is improved as well as the monochromaticity of X-rays, and the irradiation intensity on the sample 2 can be significantly increased.

FIG. 5 is a schematic view showing another example of the arrangement of the dispersive crystal 13, the X-ray focus A and the irradiation position B in FIG. The dispersive crystal 13 slightly bends a flexible thin crystal, and the crystal plane is curved in a shape forming a part of the parabola PC. As with an optical system using a parabolic mirror, the dispersive crystal 13 has a specific wavelength. Concerning the X-rays, a converging optical system in which the X-rays diverging from one point are converged into a parallel beam is configured. The X-ray focus A of the X-ray generator 10 is located at the focus of the parabola PC.

The X-ray emitted from the X-ray focal point A at the divergence angle α is diffracted and reflected by the crystal plane of the dispersive crystal 13, and then travels toward the irradiation position B as a parallel beam having a convergence angle β = 0.
Therefore, even if an error occurs in the arrangement or the shape, the convergence angle β can be made extremely smaller than the divergence angle α, and the total reflection condition for the sample 2 can be easily satisfied. In this way, X-ray monochromatization and X-ray utilization efficiency are improved.
It is possible to remarkably increase the irradiation intensity.

FIG. 6 is an enlarged view showing the X-ray diffraction condition in the converging optical system of FIGS. 4 and 5, and FIG. 6A shows the case where the surface spacing d of the diffraction grating surface is constant, and FIG. ) Indicates a case where the surface spacing d of the diffraction grating surface changes depending on the place. When the X-ray incident angle and the X-ray diffraction angle with respect to the diffraction grating surface of the dispersive crystal 13 are θ, the surface spacing of the diffraction grating surface is d, and the wavelength of the monochromatic X-ray is λ, the Bragg condition 2 · d · sin
X-ray diffraction is realized when θ = n · λ (where n is a natural number) is satisfied.

First, in FIG. 6A, in the dispersive crystal 13 made of graphite, lithium fluoride, or the like, the X-ray from the X-ray focus A is dissipated because the surface spacing d of the diffraction grating surface is constant regardless of the location. When the light enters the near region of 13, the Bragg condition 2 · d · sin θ = n · λ is satisfied.

On the other hand, the X-ray from the X-ray focal point A is the analyzing crystal 1
When incident on a far region of 3, the X-ray incident angle is θa (<
θ), so the Bragg condition 2 · d · sin θa
= N · λa holds. Therefore, among the X-rays directed to the irradiation position B, the wavelengths that satisfy the Bragg condition differ depending on the incident position of the dispersive crystal 13, which is a factor that deteriorates the monochromaticity of the X-rays. This can be ignored if the divergence angle from the X-ray focal point A is small, but if the divergence angle is increased to improve the X-ray utilization efficiency, monochromaticity is sacrificed.

Next, in FIG. 6 (b), in the dispersive crystal 13 such as the artificial cumulative multilayer film, it is possible to change the surface spacing d of the diffraction grating surface depending on the location, and the X from the X-ray focal point A can be changed.
When the line is incident on the near region of the dispersive crystal 13, the Bragg condition 2 · d · sin θ = n · λ is satisfied.

On the other hand, the X-ray from the X-ray focus A is the dispersive crystal 1.
When incident on a far region of 3, the X-ray incident angle is θa (<
θ), but since the surface distance d changes to da so as to correct this change, the Bragg condition 2 · da · sin θa = n · λ is satisfied for the X-rays of the same wavelength λ. be able to. Therefore, X toward the irradiation position B
The wavelength of the line does not depend on the incident position of the dispersive crystal 13,
Even if the divergence angle from the X-ray focal point A is large, the monochromaticity of X-rays can be improved. The distribution of the surface spacing d of the diffraction grating surface is mathematically determined by the shape of the ellipse EC or the parabola PC, the relative position of the dispersive crystal 13 and the X-ray focus A, the shape of the dispersive crystal 13, the X-ray wavelength used, and the like. Can be calculated.

FIG. 7 is a constitutional view showing a method of manufacturing the dispersive crystal 13 in which the spacing d between the diffraction grating surfaces is spatially changed. FIG. 7 shows an example in which the artificial cumulative multilayer film is deposited on the substrate 34 by using the CVD (chemical vapor deposition) method or the sputtering method. The target 31 made of a film forming material is irradiated with the ion beam 30 accelerated at high speed to
One atom is knocked out, and the released atom 32 is transferred to the substrate 34.
To deposit. Between the target 31 and the substrate 34,
A shutter 33 driven by a drive device 35 is installed under the command of the computer 36, and is controlled to be movable in parallel with respect to the substrate 34.

There are combinations of tungsten and carbon and combinations of molybdenum and silicon as film forming materials. The film forming material is selected by replacing the target 31, the irradiation energy and irradiation time of the ion beam 30, the shutter 33.
The film thickness formed on the substrate 34 can be changed depending on the location by adjusting the moving speed and the like. The artificial cumulative multilayer film thus obtained is used as the X-ray reflection type dispersive crystal 13 which is less affected by the substrate 34.

FIG. 8 is an explanatory view showing a specific example of the dispersive crystal 13. The length of the dispersive crystal 13 is about 30 mm, the distance AM between the X-ray focus A and the center M is M, the center is M, the end on the X-ray focus A side is L, and the end on the irradiation position B side is N. =
175 mm, distance between center M and irradiation position B MB = 306 m
Set to m. The X-ray used is the W-Lβ1 line with a wavelength λ =
In the case of 1.2818Å, the X-ray incident angle θ and the surface spacing d of the dispersive crystal 13 are as shown in Table 1 below.

[0044]

[Table 1]

Between L and M and between M and N, X
The surface distance d continuously changes according to the change of the line incident angle θ.

By spatially changing the plane spacing of the dispersive crystal according to the X-ray incident position, the X-ray focusing efficiency can be improved.

[0047]

As described in detail above, according to the present invention, the X-rays monochromated by the dispersive crystal can be efficiently focused on the sample, so that the utilization efficiency of X-rays from the X-ray generating means is improved, The intensity of the excited X-ray can be remarkably improved. Further, the increased excitation X-ray intensity improves the signal S / N ratio and the measurement resolution, and shortens the measurement time. In addition, as the X-ray utilization efficiency improves,
It is possible to reduce the size and weight of X-ray generators such as X-ray tubes.
Realizes downsizing of equipment and reduction of operating costs.

[Brief description of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a schematic view showing the arrangement of a dispersive crystal 13, an X-ray focus A and an irradiation position B in FIG.

FIG. 3 is a block diagram showing another embodiment of the present invention.

4 is a schematic diagram showing an example of the arrangement of the dispersive crystal 13, the X-ray focal point A, and the irradiation position B in FIG.

5 is a schematic diagram showing another example of the disposition of the dispersive crystal 13, the X-ray focus A, and the irradiation position B in FIG.

FIG. 6 is an enlarged view showing an X-ray diffraction condition in the focusing optical system of FIGS. 4 and 5, and FIG. 6A shows a case where the surface spacing d of the diffraction grating surface is constant, and FIG. The case where the surface spacing d of the diffraction grating surface changes depending on the location is shown.

FIG. 7 is a configuration diagram showing a method of manufacturing the dispersive crystal 13 in which the spacing d between the diffraction grating surfaces is spatially changed.

FIG. 8 is an explanatory diagram showing a specific example of the dispersive crystal 13.

[Explanation of symbols]

 1 Fluorescent X-ray analyzer 2 Sample 3, 4 X-ray flux 5 Fluorescent X-ray 10 X-ray generator 11 Rotating anticathode 12 Filament 13 Spectroscopic crystal 14, 15 Collimator 16 Slit 17 X-ray counter 20 X-ray detector 21 Preamplifier 22 Proportional amplifier 23 Wave height analyzer 24 Data processor 25 Table drive unit 26 Control unit 33 Shutter A X-ray focus B Irradiation position

Claims (5)

[Claims] 1. An X-ray generator for generating X-rays for excitation, and an X-ray for monochromaticizing the X-rays generated by the X-ray generator.
An X-ray fluorescence analyzer comprising: a line diffracting unit; and an X-ray detecting unit for irradiating a sample with monochromatic X-rays separated by the X-ray diffracting unit to detect fluorescent X-rays generated from the sample, The X-ray diffracting means is a dispersive crystal whose crystal plane is curved, and the dispersive crystal, the X-ray focus of the X-ray generating means, and the irradiation position of the sample are respectively arranged on the Rowland circle. A characteristic X-ray fluorescence analyzer. 2. X-ray generating means for generating X-rays for excitation, and X for monochromaticizing the X-rays generated by the X-ray generating means.
An X-ray fluorescence analyzer comprising: a line diffracting unit; and an X-ray detecting unit for irradiating a sample with monochromatic X-rays separated by the X-ray diffracting unit to detect fluorescent X-rays generated from the sample, The X-ray diffracting means is a dispersive crystal whose crystal plane is curved to form a part of an ellipse, and the X-ray focus of the X-ray generating means and the irradiation position of the sample are arranged at the focus of the ellipse, respectively. An X-ray fluorescence analyzer characterized in that 3. X-ray generation means for generating X-rays for excitation, and X for monochromaticizing the X-rays generated by the X-ray generation means.
An X-ray fluorescence analyzer comprising: a line diffracting unit; and an X-ray detecting unit for irradiating a sample with monochromatic X-rays separated by the X-ray diffracting unit to detect fluorescent X-rays generated from the sample, The X-ray diffracting means is a dispersive crystal whose crystal plane is curved to form a part of a parabola, and the X-ray focal point of the X-ray generating means is arranged at the focal point of the parabola. X-ray analyzer. 4. The fluorescence according to claim 2, wherein the X-ray is irradiated so as to be totally reflected on the sample surface, and the fluorescent X-ray generated from the sample surface in a direction other than the total reflection direction is detected. X-ray analyzer. 5. The X-ray diffracting means is an X-ray for a diffraction grating surface.
Bragg condition 2 · d · sin θ = n · λ (where n is 1), where θ is the incident angle and X-ray diffraction angle, d is the spacing between diffraction grating surfaces, and λ is the wavelength of monochromatic X-rays.
The above-mentioned natural number) is satisfied, and even if the X-ray incident angle θ changes depending on the X-ray incident position, the diffraction grating surface spacing d changes depending on the location so that the wavelength λ becomes constant. The X-ray fluorescence analyzer according to claim 2 or 3, characterized in that.